What is it?
The Water Tank Capacity Calculator tells you how much water a tank holds. It shows the capacity in litres, cubic feet and gallons, and how much water is in it at a given level.
Who is it for?
Homeowners, builders, farmers and housing societies sizing or checking water tanks and sumps.
How to use it
- Choose the Tank shape: Round (cylinder), Rectangular, or Round, lying down (horizontal).
- Enter the inside sizes: Diameter, or Length and Width, and the Height.
- Optionally, enter the Water level (optional) to see how much water is in it now.
Measure the inside
Plastic and concrete tanks have thick walls; measuring outside overstates the capacity. For a round tank, measure across the middle for the diameter.
Horizontal tanks
In a tank lying on its side, water volume isn’t proportional to the level: half the height is half full, but a quarter of the height is much less than a quarter full. The calculator handles this correctly.
Quick reference
1 cubic metre = 1,000 litres; 1 cubic foot = 28.3 litres. A family of four uses roughly 500–600 litres a day for household needs in India.
Worked example
A 6 ft × 4 ft × 4 ft rectangular tank holds 96 cubic feet, about 2,718 litres.
Errors and how to fix them
- Water now larger than capacity: the water level is taller than the tank height.
Open the tool: Water Tank Capacity Calculator
Still stuck?
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Questions, or an error not listed here?
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